[GRASSGUI] Use of monitors

[Glynn Clements]

Jachym Cepicky wrote:

> > MapLayer.Render() tries to start a monitor:
> >
> >                 if os.system("d.mon --quiet start=gism"):
> >
> > Why?
>
> hmm, is that not necessary to be able to use d.* commands ?

No. If you set GRASS_RENDER_IMMEDIATE=TRUE, d.* commands will generate
PPM/PGM (or PNG) files directly (aka direct rendering). All of the
environment variables which apply to the PNG driver apply to d.*
commands.

This is how gis.m (the Tcl/Tk one) generates images.

-- 
Glynn Clements <glynn at gclements.plus.com>